ASA 127th Meeting M.I.T. 1994 June 6-10

5pSP48. Spontaneous adult judgments of infant vowel productions.

Tamiko Ichijima

Dept. of Linguist., Sophia Univ., Tokyo-102 Japan

Francisco Lacerda

Stockholm Univ., S-106 91 Stockholm, Sweden

This study is a pilot investigation of how adult listeners spontaneously
perceive the vowel quality in infant utterances. Recordings of two Japanese
infants from the Tokyo area were used to generate the stimuli. One infant was
recorded every week between 17 to 24 weeks of age. The other infant was
recorded twice, at 32 and 78 weeks of age. The sessions lasted for about 1 h
and included playing alone, playing with the mother, and eating. The stimuli
for the perceptual evaluation were a random sample consisting of 57 utterances,
drawn from the pool of noise and interference-free utterances. Four
phonetically trained subjects judged tongue height and frontness in a speeded
judgment test paradigm. The results are compatible with the data from earlier
acoustic studies [Davis and MacNeilage, J. Speech Hear. Res. 33, 16--27
(1990)], using careful phonetic transcription. Japanese infants explore the
opening dimension during the earlier period of babbling. Although the data
cannot be used to establish the exact point at which front/back differentiation
starts to occur, a significant difference was observed between the use of that
dimension at 32 and at 78 weeks of age. [Research supported by The Bank of
Sweden Tercentenary Foundation, Grant 90-0150.]